The invention relates to distributed lighting systems.
Distributed lighting systems distribute light from one or more light sources in central or strategic locations to one or more remote locations. A distributed lighting system promises several advantages over conventional lighting techniques, including low power consumption, extended life, heat reduction where the light is emitted, and increased design flexibility.
The invention provides a distributed lighting system (DLS) for use, for example, in an automobile. Issues associated with incorporating a distributed lighting system into an automobile are discussed by Hulse, Lane, and Woodward in xe2x80x9cThree Specific Design Issues Associated with Automotive Distributed Lighting Systems: Size, Efficiency and Reliability,xe2x80x9d SAE Technical Paper Series, Paper No. 960492, which was presented at the SAE International Congress and Exposition, Detroit, Mich., Feb. 26-29, 1996, and Hulse and Mullican in xe2x80x9cAnalysis of Waveguide Geometries at Bends and Branches for the Directing of Light,xe2x80x9d SAE Technical Paper Series, Paper No. 981189, which are incorporated herein by reference.
A practical distributed lighting system for an automobile must address size, efficiency, and reliability issues. To this end, an implementation of the invention employs focus-less optics components, such as collector elements and waveguides. These components are inexpensive to manufacture, since they can be formed from plastic (acrylic, for example) in an injection molding process. In addition, they have high collecting efficiency and are very compact. For example, a collector element may be smaller than one cubic inch (16.4 cubic centimeters). Components that must handle high heat levels (e.g., components are placed in proximity to the light source) may require a ventilation system or may include portions formed from heat resistant materials, such as glass or Pyrex(trademark).
The three most demanding lighting functions in automotive illumination systems are headlamp high beams, headlamp low beams, and stop lights. These functions may be implemented using a centralized light source having waveguide outputs that transmit the light to the appropriate output points on the vehicle (i.e., the headlamps and stop lights) and form beam patterns at each output location. However, inefficiencies in the light distribution components may make such a configuration impractical. One solution to this problem is to form a hybrid lighting subsystem by combining a conventional optical system, such as a headlamp, with components that receive light from the headlamp and transmit the light through waveguides or fiber optics to provide other lighting functions throughout the vehicle.
Four hybrid lighting subsystems, each including a high intensity discharge (HID) source, should provide enough light for an entire automobile. Less efficient systems may require additional HID sources. The HID source acts as a primary light source for a particular lighting function, such as a headlamp. In addition, the HID acts as a light source for other lighting functions throughout the vehicle. Light sources other than a HID source, such as high intensity infrared (HIR), halogen, cartridge bulbs, printed circuit (PC) bulbs, and other gas discharge and incandescent bulbs, may be used. The hybrid subsystem may employ focus-less optics (FLO) to receive and transmit light from the light source. Focus-less optics components include optical waveguides and collector elements, such as are described below and in U.S. application Ser. No. 08/697,930 (xe2x80x9cDistributed Lighting Systemxe2x80x9d, filed Sep. 3, 1996) and Ser. No. 08/791,683 (xe2x80x9cOptical Waveguide Elements for a Distributed Lighting Systemxe2x80x9d, filed Jan. 30, 1997), both which are incorporated herein by reference. A hybrid tail light subsystem may be used to provide stop lights, turn signals, backup lights, and a center high-mounted stop light (CHMSL).
A vehicle distributed lighting system may include hybrid headlamp subsystems, turn signal subsystems, and hybrid tail light subsystems. The hybrid headlamp subsystems may provide primary forward illumination for the vehicle. The headlamp subsystems may be light sources for other exterior lights, such as front turn signals of the subsystems and side markers, as well as interior lights, such as dashboard lights and dome lights. These other lights may be connected to the headlamp subsystems by optical waveguides. Similarly, the tail light subsystems provide light for rear turn signals and a center high mounted stop light. The subsystems of the DLS are interconnected so that the light source of one subsystem serves as a redundant light source for another subsystem.
The DLS may incorporate different types of optical waveguide structures to distribute light throughout the vehicle, including joints, elements with epoxy coatings, pinched end collector portions, integrated installation snaps, integrated input optics and integrated output lenses. The DLS may also include waveguide structures to provide illumination to portions of the vehicle interior, including cup holders, assist grips, storage pockets step-up boards and running boards.
In one aspect, generally, an optical waveguide structure for distributing light from a light source includes a cylindrical sleeve configured to accommodate and receive light from a light source. The sleeve includes a central axis. A waveguide collar is formed from a solid, planar block of material. The block of material has a central portion configured to accommodate and surround the sleeve. The first and second output arms extend in a plane away from the central portion. The plane is substantially perpendicular to the central axis.
Embodiments may include one or more of the following features. The sleeve may be configured to confine a portion of light from the light source through internal reflection and to transmit the light away from the light source in the direction of the central axis. The sleeve may be longer in the direction of the central axis than a thickness of the central portion in that direction. The sleeve may have rim portions that are positioned to define gaps, the gaps being configured to accommodate locking tabs of a lamp base.
An integral lens portion may be formed at an end of the first arm. The first and second arms may be optical waveguides that are positioned on a surface of the waveguide collar. The waveguides may extend across the surface of the waveguide collar and beyond an edge of the waveguide collar. The first and second arms may be optical waveguides that protrude above a top surface and below a bottom surface of the waveguide collar.
In another aspect, a waveguide collar for distributing light from a light source includes a solid, planar block of material. The block of material has a central portion that accommodates a light source. The central portion surrounds the light source in a plane. First and second output arms extend in the plane away from the central portion. The thickness of the central portion in a direction perpendicular to the plane is less than a thickness of the output arms in the direction perpendicular to the plane.
Embodiments may include one or more of the following features. A cylindrical sleeve may accommodate and receive light from a light source. The sleeve may be positioned within the central portion.
In another aspect, a waveguide collar for distributing light from a light source includes a solid, planar block of material. The block of material has a hub defining an interior portion configured to accommodate a light source. The hub has side surfaces on an exterior portion. Alignment notches are positioned on the side surfaces. The notches are configured to receive an alignment tab of a waveguide. Rim portions extend around the interior portion of the hub. The rim portions are positioned to define gaps that accommodate locking tabs of a lamp base.
In another aspect, a waveguide collar for distributing light from a light source includes a solid, planar block of material. The block of material has a central portion that accommodates a light source. The central portion surrounds the light source in a plane. First and second output arms extend in a plane away from the central portion. The sides of the first and second output arms curve inward toward the central portion to form first and second vertices where the first and second arms meet. A lens is formed on an edge of the waveguide collar. The lens receives light from the light source, focuses a portion of the light, and transmits the portion of the light away from the collar.
In another aspect, an optical waveguide includes first and second pieces of solid material. The first piece has a transmission portion having a rectangular cross-section and an end that is convex in one dimension. The second piece has a transmission portion having a rectangular cross-section and an end that is concave in one dimension. The end of the first piece and the end of the second piece form an interface between the first piece and the second piece.
Embodiments may include one or more of the following features. A third piece of solid material may have a transmission portion having a rectangular cross-section and an end that is concave in one dimension. The end of the third piece and the end of the first piece may form an interface between the third piece and the first piece. A band may hold the first, second and third pieces together.
A third piece of solid material may have a transmission portion having a rectangular cross-section and an end that is convex in one dimension. The end of the third piece and the end of the second piece may form an interface between the third piece and the second piece. A band may hold the first, second and third pieces together.
In another aspect, an optical waveguide for accepting light from a light source and transmitting the light includes a piece of solid material having an input face, a transmission portion, and an end portion between the input face and the transmission portion. A cross-sectional area of the end portion gradually decreases from the transmission portion to the input face.
Embodiments may include one or more of the following features. The end portion may have planar sides angled from a longitudinal axis of the transmission portion. The angle formed between the sides and the longitudinal axis may be about 5xc2x0. The end portion may increase an acceptance angle of the waveguide. A lens portion may be formed on the input face.
In another aspect, an optical waveguide has integrated installation elements. The waveguide includes first and second sections. The first section includes an input face, an output end and a transmission portion extending from the input face to the output end. A key positioned on the output end mates with a socket of the second section. The second section includes an input face, an output end and a transmission portion extending from the input face to the output end. A socket positioned on the output end mates with a key of the first section.
Embodiments may include one or more of the following features. A snap positioned on the transmission portion of the first or second section may mate with an installation fitting of a vehicle. An outer surface of the waveguide may be covered with epoxy.
In another aspect, an optical waveguide includes first and second sections. The first section includes an input face, an output end and a transmission portion extending from the input face to the output end. A claw positioned on the output end mates with a detent of the second section. The second section includes an input face, an output end and a transmission portion extending from the input face to the output end. A detent positioned near the output end mates with the claw of the first section.
In another aspect, an optical waveguide has an output element for providing illumination in a vehicle. The waveguide includes an input face and a transmission portion extending from the input face. The transmission portion widens at an end to form an output element having a convex lens at the end. The output element may be formed to leave an air gap between the lens and the end of the transmission portion.
Other features and advantages will be apparent from the following detailed description, including the drawings, and from the claims.